Symptoms and Signs of Psoriasis

Psoriasis Symptoms

Plaque psoriasis (psoriasis vulgaris), the most common form, usually produces plaques of red, raised, scaly skin affecting the scalp, elbows, and knees. The plaques may itch or burn.

Plaque psoriasis on the elbow. Image courtesy of Hon Pak, MD.

The flare-ups can last for weeks or months. Psoriasis can spontaneously resolve only to return later.

General characteristics:

• Plaques: They vary in size (1 centimeter to several centimeters) and may be stable for long periods of time. The shape of the plaque is usually round with irregular borders. Smaller plaques may merge, producing extensive areas of involvement.

Plaque psoriasis. Image courtesy of Hon Pak, MD.

The skin in these areas, especially when over joints or on the palms or feet, can split and bleed.

Plaque psoriasis with fissures, which are splits in the skin. Fissures usually occur where the skin bends (joints). The skin may bleed and is more susceptible to infection. Image courtesy of Hon Pak, MD.

Plaques sometimes may be surrounded by a halo or ring of blanched skin (Ring of Woronoff). This is especially noticeable after effective treatment has begun and the lesions are resolving.

• Red color: The color of the affected skin reflects the inflammation present and is caused by increased blood flow.
• Scale: The scales are silvery white. The thickness of the scales may vary. When the scale is removed, the skin underneath looks smooth, red, and glossy. This shiny skin usually has small areas of pinpoint bleeding (Auspitz sign).
• Symmetry: Psoriatic plaques tend to appear symmetrically on both sides of the body. For example, psoriasis is usually present on both knees or both elbows.

Psoriasis of the scalp. Image courtesy of Hon Pak, MD.

• Nails: Nail changes are common in psoriasis. The nails may have small indentations or pits. The nails can be discolored and separate from the nail bed at the fingertip. (See Nail Psoriasis.) This may be similar in appearance to fungal nail infections and may actually coexist with, a fungal infection.

Nail psoriasis. Note the classic pits and yellowish color in the nails. Image courtesy of Hon Pak, MD.

• Psoriasis in children: Plaque psoriasis may look slightly different in children. In children, the plaques are not as thick, and the affected skin is less scaly. Psoriasis may often appear in the diaper region in infancy and in flexural areas in children. The disease more commonly affects the face in children as compared to adults.
• Other areas: Although the most common body areas affected are the arms, legs, back, and scalp, psoriasis can be found on any body part. Inverse psoriasis can be found on the genitals or buttocks, under the breasts, or under the arms and may not show the scale typically seen in other body areas. These areas can feel especially itchy or have a burning sensation.

Psoriasis on the palms. Image courtesy of Hon Pak, MD.

Psoriasis Causes

Research indicates that the disease results from a disorder in the inflammatory system. In psoriasis, T lymphocytes (a type of white blood cell) abnormally trigger inflammation in the body. These T cells also stimulate skin cells to grow faster than normal and to pile up in raised plaques on the outer surface of the skin.

Those with a family history of psoriasis have an increased chance of having the disease. Some people carry genes that make them more likely to develop psoriasis. When both parents have psoriasis, their offspring have a 50% chance of developing psoriasis. About one-third of those with psoriasis can recall at least one family member with the disease.

Certain risk factors may trigger a psoriasis flare.

• Injury to the skin: Injury to the skin has been associated with plaque psoriasis. For example, a skin infection, skin inflammation, or even excessive scratching can trigger psoriasis at the site of the skin injury.
• Sunlight: Most people generally consider sunlight to be beneficial for their psoriasis and therapeutic phototherapy is a treatment option. However, a small minority find that strong sunlight aggravates their condition. A bad sunburn may worsen psoriasis.
• Streptococcal infections: Streptococcal sore throats may trigger guttate psoriasis, a type of psoriasis that looks like small red drops on the skin.

Guttate psoriasis. Red drop-like lesions are found on the skin. This type of psoriasis usually occurs after a streptococcal (bacterial) infection. Image courtesy of Hon Pak, MD.

• HIV: Psoriasis may worsen after an individual has been infected with HIV.
• Drugs: A number of medications have been shown to aggravate psoriasis. Some examples are as follows:
  • Lithium: Drug that may be used to treat bipolar disorder
  • Beta-blockers: Drugs that may be used to treat high blood pressure
  • Antimalarials: Drugs used to treat malaria, arthritis, and lupus
  • NSAIDs: Drugs, such as ibuprofen (Motrin and Advil) or naproxen (Aleve), used to reduce inflammation
• Emotional stress: Many people note worsening of their psoriasis when emotionally stressed.
• Smoking: Cigarette smokers have an increased risk of chronic plaque psoriasis because smoking may alter the immune system in such a way as to cause a flare of the condition.
• Alcohol: Alcohol is considered a risk factor for psoriasis. Even moderate intake of beer may trigger or worsen psoriasis.
• Hormonal changes: The severity of psoriasis may fluctuate with hormonal changes. Disease frequency peaks during puberty and menopause. During pregnancy, psoriatic symptoms are more likely to improve. In contrast, flares occur in the postpartum period.